WO2013000396A1 - Electronic expansion valve - Google Patents

Abstract

Disclosed in the present invention is an electronic expansion valve, which comprises a valve seat assembly (7) and a valve housing assembly (5) connected to the valve seat assembly (7). A valve stem assembly (6) and a valve port (121) are disposed in the chamber of the valve seat assembly (7), and an electrical motor (51) is situated in the chamber of the valve housing assembly (5). The electrical motor (51) drives the valve stem assembly (6) to move along an axial direction through a gear system (52) so as to adjust the flow rate of the fluid flowing through the valve port (121). The valve seat assembly (7) has a split structure, which comprises a valve seat (1) and a cover (9) connected to the valve seat (1) and to the valve housing assembly (5). A mounting surface (13) is formed on the outer side of the valve seat (1) and a sight glass (8) is connected thereon. The structure of the expansion valve enables the sight glass (8) to be easily attached to the valve seat assembly (7).

Description

 The present application claims the priority of the Chinese Patent Application No. 201110175269.X, entitled "Electronic Expansion Valve", which is incorporated herein by reference. in. Technical field

 The invention relates to the technical field of fluid control components, and in particular to an electronic expansion valve. Background technique

 The electronic expansion valve is an important component of the refrigeration system and is another essential component in the four basic components of the refrigeration system, except for the evaporator, compressor and condenser. The operation of the electronic expansion valve is generally as follows: As the coil unit is energized or de-energized, the valve needle adjusts the opening of the valve port to regulate the flow rate of the refrigerant.

 In the prior art, U.S. Patent No. 5,735,501 discloses an electronic expansion valve. Referring specifically to Figure 1, Figure 1 is a schematic view of the structure of an electronic expansion valve in the prior art.

 As shown in FIG. 1, the prior art electronic expansion valve includes a valve seat assembly 1' and a housing assembly 2'. The valve seat assembly 1' is provided with a valve stem assembly 3' and a valve port 1 Ί. The motor 2 is provided therein, and the motor 2Ί drives the valve stem assembly 3' to move up and down in the axial direction through the gear system 2'2, thereby regulating the flow of fluid through the valve port 1Ί. However, the prior art electronic expansion valve has the following disadvantages:

In the above electronic expansion valve, the valve seat assembly 1' is an integral sleeve member made of a thin-walled tensile member or a stainless steel tube. Since the side wall of the valve seat assembly 1' is circular, the process of connection with the sight glass is poor, and since the saddle surface is present at the connection position of the side wall of the valve seat assembly 1', the 0-ring cannot be mounted. , poor sealing. In addition, due to the presence of the saddle surface described above, the sight glass and the valve seat assembly 1' are also not easily threaded. If a threaded connection is necessary, the wall thickness of the cylindrical valve seat assembly 1' is increased. This results in wasted material, increased costs, and makes the product bulky. In summary, the above-mentioned prior art electronic expansion valve is not suitable for mounting a sight glass, and since there is no sight glass, the internal fluid of the electronic expansion valve cannot be grasped in time. The situation will cause inconvenience to the customer to apply the electronic expansion valve.

 In addition, the Chinese patent No. 200580023202.7 also discloses an electronic expansion valve. In the electronic expansion valve, as shown in Fig. 2, since the structure of the valve seat assembly 22 is complicated, the valve seat assembly 22 is first formed into a blank by a brass casting, and then machined. First, the nature of the casting process determines that the material will inevitably contain defects such as slag inclusions and pores. Therefore, after the product is installed outdoors for a period of time, corrosion will produce patina, and the defective part is the weakest. The pressure in the refrigeration system is significantly higher than the outside of the valve, which is prone to leakage or insufficient strength and the valve body is broken, which affects the product life and reliability, which will cause the function of the entire refrigeration unit to fail, for large-scale cold storage, supermarket cold rejection or cold storage. Fresh food brings huge losses. Second, because the melting point of brass is more than 930 degrees, therefore, in the tunnel furnace with reducing agent shielding gas, the welding temperature of the process must be lower than the melting point of brass; therefore, the nozzle must be welded to the brass valve body. The use of high-silver solders has led to a significant increase in welding costs as silver prices have risen. Third, because the brass casting is processed by the mold, if the customer has different requirements, the connection position of the take-over and the valve seat needs to be adjusted, so that the casting mold is re-opened; however, the production cycle of re-opening the casting mold is long, resulting in an increase in production cost.

 In view of this, how to improve the electronic expansion valve of the prior art so that the sight glass can be connected to the valve seat assembly more conveniently is an urgent problem to be solved by those skilled in the art. Summary of the invention

 SUMMARY OF THE INVENTION The technical problem to be solved by the present invention is to provide an electronic expansion valve which is structurally designed to allow a sight glass to be more easily attached to a valve seat assembly, and which can easily ensure the connection process and connection quality.

 In order to solve the above technical problems, the present invention provides an electronic expansion, including a wide seat assembly and a housing assembly connected to the wide seat assembly; the wide seat assembly has a wide rod assembly and a valve port therein. a motor is disposed in the inner cavity of the outer casing assembly, and the motor drives the valve stem assembly to move axially to regulate the flow of fluid through the valve port through a gear system; the valve seat assembly is a split structure, including a valve seat and a connection a cover on the valve seat, the cover is connected to the outer casing assembly; a mounting plane is formed on an outer side of the valve seat, and a sight glass is connected to the mounting plane.

Preferably, the valve seat is further a split structure, including an upper valve seat and connected to the upper valve seat The cover is further connected to the upper wide seat; the mounting plane is further formed on an outer side of the upper valve seat.

 Preferably, the upper valve seat is further a square valve seat, and any outer side surface of the square valve seat forms the mounting plane.

 Preferably, the valve port is disposed on the lower valve seat, and the valve port protrudes upward in the axial direction with a sleeve extending portion, and the sleeve protruding portion extends into the cavity of the upper wide seat In the body, the wide rod assembly is provided with a tubular valve stem; an opening groove for adjusting the flow rate is opened on a circumferential side wall of one of the sleeve extension portion and the lower end portion of the valve stem, and One of the sleeve extension and the lower end of the valve stem extends into or out of the other to interrupt the communication or communication of the open slot with the valve port.

 Preferably, the wide seat is further a unitary structure, and the wide seat is integrally a square body, and any outer plane of the square valve seat forms the mounting plane.

 Preferably, the valve port is provided with a first step surface in a circumferential direction; the valve stem assembly includes a tubular valve stem, and a second step surface and an opening groove for adjusting a flow rate are opened on a sidewall of the lower end portion of the valve stem; The lower end portion of the valve stem extends into or protrudes from the valve opening such that the first step surface is in sealing or disengagement contact with the second step surface.

 Preferably, the mounting plane is provided with a threaded hole, and the sight glass comprises a mirror base, and the mirror base is connected to the threaded hole by a threaded fit.

 Preferably, a sealing member is further disposed between the mirror base and the hole wall of the threaded hole. Preferably, the outer casing assembly includes a housing and a pin base connected to the outer casing, and the outer casing assembly is coupled to the cover by the outer casing, and the pin base is injection molded with a pin.

 Preferably, the wide seat assembly is further a stainless steel wide seat assembly.

 Based on the prior art, the valve seat assembly of the electronic expansion valve provided by the present invention is a split structure, including a valve seat and a cover connected to the valve seat, the cover being connected to the outer casing assembly A mounting plane is formed on an outer side surface of the valve seat, and a sight glass is connected to the mounting plane.

Compared to the prior art, the valve seat assembly provided by the present invention is a split structure including a valve seat and a cover, which is a cylindrical member that is easily connected to the outer casing assembly. Since the valve seat is separated from the cover, the valve seat can be made of a non-cylindrical member. For example, a square seat or a valve seat of other shapes that is easy to machine the mounting surface can be used, so that it can be easily mounted on the valve seat. flat. Relative to the horse The structural design of the sight glass connected to the saddle surface, the structural design of the sight glass connected to the mounting plane enables the connection of the sight glass to be facilitated, and the connection process and the connection quality are also easily ensured.

 In summary, the electronic expansion valve of the present invention is structurally designed to allow the sight glass to be more easily attached to the valve seat assembly, and the connection process and connection quality can be easily ensured. DRAWINGS

 1 is a schematic structural view of an electronic expansion valve in the prior art;

 2-1 is a schematic structural view of an electronic expansion valve according to a first embodiment of the present invention;

 2-2 is a schematic structural view of the electronic expansion valve of FIG. 2-1 at another viewing angle; FIG. 3-1 is a schematic structural view of an electronic expansion valve according to a second embodiment of the present invention;

 Figure 3-2 is a structural view of the electronic expansion valve of Figure 3-1 from another perspective; Figure 4 is a cross-sectional view of the electronic expansion valve of Figure 2-1;

 Figure 4-1 is a schematic view showing the cooperation structure of the valve stem and the lower valve seat of the electronic expansion valve of Figure 4; Figure 4-2 is an isometric view of the lower valve seat of Figure 4-1;

 4-3 is a schematic view showing the cooperation structure of the valve stem and the lower valve seat in another embodiment;

 Figure 5 is a cross-sectional view of the valve seat assembly and the sight glass of the electronic expansion valve of Figure 3-1; Figure 5-1 is a schematic view of the cooperation structure of the valve seat and the valve stem of Figure 5;

 Figure 6 is a schematic structural view of the outer casing assembly of Figures 2-1 to 3-2;

 Figure 6-1 is a plan view of the housing assembly of Figure 6;

 Figure 6-2 is a bottom plan view of the housing assembly of Figure 6.

 Wherein, the correspondence between the reference numerals and the component names in FIG. 1 is:

 1's seat assembly; 1Ί valve port; 2' housing assembly; 2Ί motor; 2'2 gear system; 3' stem assembly;

 The correspondence between the reference numerals and the part names in Figures 2-1 to 6-2 is:

 1 valve seat; 11 upper valve seat; 12 lower valve seat; 121 valve port; 122 sleeve extension; 123 first sealing surface; 13 mounting plane; 14 first step surface;

 2 valve stem; 21 second step surface; 22 second sealing surface;

 3 open slot; 41 first take-over; 42 second take-over;

5 housing assembly; 51 motor; 52 gear system; 53 housing; 54 pin base; 55 pin; 56 glass alloy; 57 anti-insertion sheath;

 6 stem assembly; 61 screw; 62 gear seat;

 7 valve seat assembly;

 8 sight glass; 81 mirror base; 82 seals; 83 paper; 84 cards; 85 lenses; detailed description

 The core of the present invention is to provide an electronic expansion valve which is structurally designed to allow the sight glass to be more easily attached to the valve seat assembly and to ensure the connection process and connection quality.

 In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

 Please refer to FIG. 2-1, FIG. 2-1, FIG. 3-1 and FIG. 3-2. FIG. 2-1 is a schematic structural view of an electronic expansion valve according to a first embodiment of the present invention; FIG. 2-2 is a diagram 2 1 is a schematic structural view of an electronic expansion valve in another view; FIG. 3-1 is a schematic structural view of an electronic expansion valve according to a second embodiment of the present invention; and FIG. 3-2 is an electronic expansion valve of FIG. A schematic diagram of the structure from another perspective.

 In the basic technical solution, as shown in FIG. 2-1 to FIG. 3-2, the electronic expansion valve provided by the present invention comprises a wide seat assembly 7 and a housing assembly 5 connected to the wide seat assembly 7; A valve stem assembly 6 and a valve port 121 are disposed in the cavity, and a motor 51 is disposed in the inner cavity of the outer casing assembly 5. The motor 51 drives the valve stem assembly 6 to move axially through the gear system 52, thereby regulating the flow of fluid through the valve port 121. .

 Based on the above structure, as shown in FIGS. 2-1 to 3-2, the valve seat assembly 7 is a split structure including a valve seat 1 and a cover 9 attached to the valve seat 1, a cover 9 and a housing The assembly 5 is connected to the outer side of the valve seat 1 with a mounting plane 13 to which a sight glass 8 is attached.

 Compared with the prior art, the valve seat assembly 7 provided by the present invention is a split structure including a valve seat.

1 and a cover 9, which is a cylindrical member that is easily connected to the outer casing assembly 5. Since the valve seat 1 is separated from the cover 9, the valve seat 1 can be a non-cylindrical member. For example, a square valve seat or a valve seat of other shapes which is easy to process a flat surface can be used, so that it can be easily mounted on the valve seat 1. The mounting plane 13 is machined. Connect the visual fluid on the mounting plane 13 relative to the structural design of the sight glass attached to the saddle The structural design of the mirror 8 enables the connection of the sight glass 8 to be facilitated, and the joining process and the quality of the connection are also easily secured.

 Based on the above basic technical solutions, further improvements can be made to obtain the first embodiment of the present invention. For details, please refer to FIG. 2-1 and FIG. 2-2. In the first embodiment, the valve seat 1 is further divided into a split structure, including an upper valve seat 11 and a lower valve seat 12 connected to the upper valve seat 11, a cover The cover 9 is further connected to the upper valve seat 11; the mounting plane 13 is further formed on the outer side surface of the upper valve seat 11. The structural design of the valve seat 1 is such that the mounting plane 13 is only opened on the upper valve seat 11, thereby making the machining process tubular; in addition, the lower valve seat 12 can be made of a material-saving cylindrical shape, thereby saving the valve. Seat material.

 Specifically, referring to Figs. 2-1 and 2-2, the upper valve seat 11 is further a square valve seat, and any outer plane of the square valve seat forms a mounting plane 13. The structural design of the square valve seat can be omitted from the mounting plane 13 of the liquid mirror 8, so that the sight glass 8 can be connected to any one of the outer planes of the square valve seat according to the specific application environment. Further, the square valve seat can be formed by a square bar, and the square bar material is low in cost and easy to obtain, so that the production cost can be remarkably reduced. In addition, the square bar is made of stainless steel, which also improves the strength and corrosion resistance of the seat.

 Further, another modification of the wide seat can be made, thereby obtaining the second embodiment of the present invention. Specifically, as shown in Figs. 3-1 and 3-2, the valve seat 1 is further integrated, and the valve seat 1 is integrally a square valve seat, and any outer plane of the square valve seat forms a mounting plane 13. The valve seat 1 is a one-piece structure, and the whole is a square valve seat. This structure design can reduce the structure of the valve seat 1, reduce the number of parts, and further the assembly process and assembly cost.

 Please refer to FIG. 4, FIG. 4-1 and FIG. 4-2. FIG. 4 is a cross-sectional view of the electronic expansion valve of FIG. 2-1; FIG. 4-1 is the cooperation of the valve stem and the lower valve seat of the electronic expansion valve of FIG. Schematic diagram of the structure; Figure 4-2 is an isometric view of the lower valve seat in Figure 4-1.

In the first embodiment described above, further improvements can be made. For example, on the basis of this, as shown in FIG. 4 to FIG. 4-2, the valve port 121 is disposed on the lower valve seat 12, and the valve port 121 protrudes upward in the axial direction with a sleeve extending. a portion 122, the sleeve projecting portion 122 extends into the cavity of the upper valve seat 11, the valve stem assembly 6 is provided with a tubular valve stem 2; the sleeve extension portion 122 and the lower end portion of the valve stem 2 One of the circumferential side walls is provided with an opening groove 3 for adjusting the flow rate, and one of the sleeve extending portion 122 and the lower end portion of the valve stem 2 projects into or protrudes from the other ( That is, the sleeve extension portion 122 extends into or protrudes from the inside of the lower end portion of the valve stem 2, or the lower end portion of the valve stem 2 projects into or protrudes from the sleeve extension portion 122 to interrupt the opening slot. 3 is in communication with or communicates with the valve port 121.

 The shape of the open groove 3 corresponds to a required flow curve, such as a V-shaped groove, a Y-shaped groove or the like, and a flow curve of what shape the refrigeration system requires, which may be on the circumferential side wall of the sleeve extension 122 or An opening groove 3 corresponding to the lower end portion of the stem 2 is opened. In operation, as the valve stem 2 and the sleeve extension portion 122 are disengaged from each other, the open groove 3 begins to flow in small flow with the valve port 121, and further disengages from the valve stem 2 and the sleeve extension portion 122, the opening groove 3 The flow area is gradually increased, and the flow rate of the refrigerant is gradually increased until the opening grooves 3 are all opened, thereby achieving maximum flow communication with the valve port 121. It can be seen that the flow regulating valve provided by the present invention can obtain the required flow rate curve.

 In addition, since the lower end portion of the valve stem 2 is a cylindrical body instead of a cone, the pressure of the refrigerant at the lower end of the valve stem 2 is uniform; meanwhile, since the valve stem 2 is tubular and penetrates in the axial direction, the valve stem 2 is thus The pressure of the refrigerant at the upper end is equal to the pressure of the refrigerant at the lower end. Under the premise that the force receiving areas of the upper end and the lower end of the valve stem 2 are equal, the refrigerant pressure of the valve stem 2 in the axial direction is balanced.

 It should be noted that, in the above embodiment, the opening groove 3 may be opened on the side wall of the sleeve extending portion 122, or the opening groove 3 may be opened at the lower end portion of the valve stem 2; in the two technical solutions, the sleeve The barrel extension portion 122 extends into or protrudes from the inside of the lower end portion of the valve stem 2, or the lower end portion of the valve stem 2 projects into or protrudes from the sleeve extension portion 122, and the opening groove 3 and the valve can be interrupted. The ports 121 are connected or connected.

As shown in FIGS. 4 to 4-2, the open groove 3 is formed on the circumferential side wall of the sleeve projecting portion 122; on the basis of this, as shown in FIGS. 4-1 and 4-2, the sleeve is extended. The portion 122 is provided with a first sealing surface 123 located lower than the lowermost end of the opening groove 3, and the first sealing surface 123 may be further disposed inside the sleeve extending portion 122; on this basis, as shown in FIG. 4-1 and As shown in Fig. 4-2, the lower end portion of the valve stem 2 projects into or protrudes from the inside of the sleeve projecting portion 122, so that the lower end surface of the base body 21 is in sealing or disengagement contact with the first sealing surface 122. In this structural design, it is the lower end surface of the base body 21 and The first sealing surface 123 is sealed, and the lower end surface of the base body 21 is hard to be deformed due to its rigidity. Therefore, compared with the structural design of the sealing sheet in the prior art, the sealing performance and the service life are significantly improved! 3⁄4.

 During processing, the valve port 121 and the sleeve extension portion 122 are first machined on the lower valve seat 12, and the open groove 3 is machined on the sleeve extension portion, and then the upper valve seat 11 is machined, and finally the processed portion is processed. The valve seat 12 and the upper valve seat 11 are assembled. It can be seen that the structural design of the valve seat 1 is very convenient to realize the processing of the sleeve extension portion 122 and the open groove, and the processing process is finished.

 In addition, as shown in FIG. 4, the first connecting pipe 41 is connected to the upper valve seat 11, and the second connecting pipe 42 is connected to the lower valve seat 12. The structure is designed to facilitate the adjustment of the first connecting pipe according to the needs of the environmental space of the refrigeration system. The positional relationship between the 41 and the second nozzle 42, for example, makes the two parallel or at an angle of 90°.

 Further improvements can be made in the first embodiment described above. For example, please refer to FIG. 4-3. FIG. 4-3 is a schematic view showing the cooperation structure of the valve stem and the lower valve seat in another embodiment.

 As shown in Fig. 4-3, it is also possible to specifically design the opening groove 3 to be provided on the lower end portion of the valve stem 2. On the basis of this, the lower end portion of the valve stem 2 is provided with a second sealing surface 22 positioned higher than the uppermost end of the opening groove 3, and further, the second sealing surface 22 may be disposed inside the lower end portion of the valve stem 2; Based on this, as shown in FIG. 4-3, the sleeve projecting portion 122 can further extend into or protrude from the lower end portion of the valve stem 2 so that the upper end surface of the sleeve projecting portion 122 and the second seal are formed. Face 22 is in contact with or out of contact. In this structural design, the upper end surface of the sleeve projecting portion 122 is sealed with the second sealing surface 22, and the second sealing surface 22 is less susceptible to deformation due to rigidity, and thus the structure of the sealing sheet relative to the prior art. The design, sealing performance and service life are significantly improved.

 Please refer to FIG. 5 and FIG. 5-1. FIG. 5 is a cross-sectional view of the valve seat assembly and the sight glass of the electronic expansion valve of FIG. 3-1; FIG. 5-1 is the cooperation structure of the valve seat and the valve stem of FIG. schematic diagram.

 Further improvements can be made in the second embodiment described above. For example, the valve port 121 is provided with a first step surface 14 in the circumferential direction; the valve stem assembly 6 includes a tubular valve stem 2, and a second step surface 21 and an opening groove 3 for adjusting the flow rate are opened on the side wall of the lower end portion of the valve stem 2; The lower end of the rod 2 projects into or out of the valve opening 121 so that the first step surface 14 is in sealing or disengagement contact with the second step surface 21. Obviously, this kind of structural design can also achieve the purpose of regulating the flow.

On the basis of any of the above technical solutions, the mounting structure of the sight glass 8 can also be made. Specific design. For example, referring to FIG. 5 and FIG. 5-1, the mounting plane 14 is provided with a threaded hole, and the sight glass 8 includes a mirror base 81, and the mirror base 81 is connected to the threaded hole by a threaded fit; A seal 82 is further disposed between the seat 81 and the bore wall of the threaded bore. The structural design of the mounting plane 13 facilitates the threaded connection between the mirror base 81 and the threaded bore, and since the sight glass 8 is attached to the mounting plane 13, rather than the saddle surface, the seal is also realized. 82 installation.

 Further, as shown in Figs. 5 and 5-1, the mirror base 81 is further provided with a lens 85, a paper 83, and a card 84 for chucking the paper 83 inside the mirror base 81. The color of the paper 83 is different at different temperatures or different phases of the refrigerant, so that depending on the color change of the paper 83, the temperature state or phase condition of the refrigerant can be generally known.

 Further, the specific structure of the outer casing assembly 5 can also be designed. For details, please refer to FIG. 6, FIG. 6-1 and FIG. 6-2. FIG. 6 is a schematic structural view of the outer casing assembly of FIGS. 2-1 to 3-2; Figure 6-1 is a plan view of the housing assembly of Figure 6; Figure 6-2 is a bottom view of the housing assembly of Figure 6.

 Specifically, as shown in FIGS. 6 to 6-2, the outer casing assembly 5 includes a casing 53 and a pin base 54 connected to the casing 53, the upper portion of the casing 53 is provided with a cap, and the center of the cap is provided with a center. The hole, the pin base 54 is connected to the center hole. Further, as shown in Fig. 6-2, the pin 55 is fixedly packaged inside the pin base 54 by a sealing material such as a glass alloy 56. As shown in Figure 6-1, the needle base 54 is also provided with an error-proof sheath 57 to prevent the connector from being inserted into the respective pins 55.

 In addition, in any of the above technical solutions, the material of the valve seat assembly 7 may be stainless steel, and the wide seat assembly 7 is specifically a stainless steel wide seat assembly. The stainless steel wide seat assembly not only has high strength but also has excellent corrosion resistance.

 Finally, it should be noted that, as shown in FIG. 4, the electronic expansion valve is provided for adjusting the flow rate of the refrigerant. As shown in FIG. 3, the electronic expansion valve includes a casing assembly 5, and the casing 51 is provided with a motor 51, a motor. The output shaft of 51 is drivingly coupled to the lead screw 61 of the valve stem assembly 6 via the gear system 52, so that the screw 61 rotates with the output shaft of the motor; as shown in FIG. 4, the gear system 52 is supported on the gear housing 62, and The screw rod 61 is connected to the valve stem 2 through the gear base 62. As the screw rod 61 rotates, the valve stem 2 moves up and down in the axial direction, thereby achieving the purpose of adjusting the refrigerant flow rate.

An electronic expansion valve provided by the present invention has been described in detail above. Application in this article It is a method for helping to understand the present invention and its core idea. It should be noted that those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the invention.

Claims

Rights request  An electronic expansion valve comprising a valve seat assembly (7) and a housing assembly (5) coupled to the valve seat assembly (7); a valve stem assembly disposed in a lumen of the valve seat assembly (7) (6) and a valve port (121), a motor (51) is disposed in the inner cavity of the outer casing assembly (5), and the motor (51) drives the valve stem assembly (6) along the gear system (52) The axial movement regulates the flow of fluid through the valve port (121); characterized in that the wide seat assembly (7) is a split structure including a wide seat (1) and a cover attached to the valve seat (1) a cover (9), the cover (9) is connected to the outer casing assembly (5); a mounting plane (13) is opened on an outer side surface of the valve seat (1), and the mounting plane (13) is connected There is a sight glass (8).  2. The electronic expansion valve according to claim 1, wherein the valve seat (1) is further a split structure including an upper valve seat (11) and a lower connection with the upper valve seat (11) Seat (12), the cover (9) is further connected to the upper valve seat (11); the mounting plane (13) Further opening on the outer side surface of the upper valve seat (11).  3. The electronic expansion valve according to claim 2, wherein the upper valve seat (11) is further a square valve seat, and any outer plane of the square valve seat forms the mounting plane (13) ).  The electronic expansion valve according to claim 2 or 3, wherein said valve port (121) is provided on said lower valve seat (12), and said valve port (121) is axially upward Projecting a sleeve extension (122), the sleeve extension (122) extending into the cavity of the upper valve seat (11), the valve stem assembly (6) being provided with a tubular valve stem (2); an opening groove (3) for adjusting a flow rate is provided on a circumferential side wall of one of the sleeve extending portion (122) and the lower end portion of the valve stem (2), and the sleeve is One of the barrel extension (122) and the lower end of the valve stem (2) extends into or out of the other to interrupt the open slot (3) and the valve port ( 121) Connect or connect.  The electronic expansion valve according to claim 1, wherein the valve seat (1) is further an integral structure, and the wide seat (1) is a square body as a whole, and the square body is wide Any outer plane forms the mounting plane (13). The electronic expansion valve according to claim 5, wherein the valve port (121) is provided with a first step surface (14) in a circumferential direction; the valve stem assembly (71) includes a tubular valve stem (2) a second step surface (21) is opened on the side wall of the lower end portion of the valve stem (2), and the flow rate is adjusted to be opened. a mouth groove (3); a lower end portion of the valve stem (2) projects into or protrudes from the valve port (121), so that the first step surface (14) and the second step surface ( 21) Contact seal or disengagement.  The electronic expansion valve according to any one of claims 1 to 6, wherein the mounting plane (14) is provided with a threaded hole, and the sight glass (8) comprises a mirror base (81) The mirror base (81) is coupled to the threaded hole by a threaded fit.  8. The electronic expansion valve according to claim 7, wherein a seal member (82) is further disposed between the mirror base (81) and the hole wall of the threaded hole.  The electronic expansion valve according to any one of claims 1 to 6, characterized in that the outer casing assembly (5) comprises a housing (53) and a pin base (54) to which the outer casing (53) is connected. The housing assembly (5) is coupled to the cover (72) through the housing (53), and the pin base (54) is injection molded with a pin (55).  The electronic expansion valve according to any one of claims 1 to 6, wherein the valve seat assembly (7) is further a stainless steel wide seat assembly.